Boring; is due to be spruced up (7)

I believe the answer is:

tedious

I'm a little stuck... Click here to teach me more about this clue!

'boring' is the definition.
(I know that boring can be written as tedious)

'is due to be spruced up' is the wordplay.
'is due to' can be anagrammed to 'TEDIOUS'.
However, I am not clear how the anagram is indicated.

Can you help me to learn more?

(Other definitions for tedious that I've seen before include "Dull as ditchwater" , "Outside (anag.)" , "not worth listening to?" , "Tiresome, boring" , "awfully boring" .)

I've seen this clue in The Globe and Mail.

Want a hint initially instead of a full solution? Install my app